The present invention relates to assignment of storage devices connected to a network.
JP-A-10-69357 discloses disk controllers connected together by a network. This prior art discloses a mechanism of exchanging a communication protocol between a host and each disk array controller for a communication protocol between disk array controllers, in a storage system connecting a plurality of disk array controllers to a network. With this mechanism, the host has a general interface and communications between disk array controllers can be performed at high speed.
Similarly, JP-A-2000-99272 discloses disk controllers connected together by a network. This prior art discloses on-line addition of a new storage controller to a fabric channel network having a plurality of storage controllers already connected thereto to make the new storage controller take over a process of a logical unit. With this arrangement, loads of the storage controllers can be distributed and process integration can be realized so that a process performance of the whole system can be improved.
In a system connecting host computers and storage devices to a network, each host computer has conventionally used a storage device or logical unit assigned beforehand.
In a storage system connecting a plurality of storage devices to a network, a plurality of host computers connected to the network can access each storage device. Access is also possible between storage devices.
In such systems, the time for a host computer to access each storage device may change with the transmission path of the network. Further, an access frequency and a backup frequency may change with each storage device, and reliability may change with each storage device.
In addition, a host computer may be required to have a fast access time or have high reliability even with a slow access time, depending upon an application program to be used.
If a storage device or logical unit is assigned in accordance with each application program, a system having a better efficiency can be configured.
It is an object of the present invention to provide a method and system capable of allowing a host computer side to assign each storage device or logical unit.
In order to achieve the above object of the invention, management information for each assignable storage area (unitary logical unit) in a plurality of storages connected to a network is stored. In assigning a logical unit of the storage in response to a user request for a virtual logical unit, an evaluation value of each storage area is calculated in accordance with the management information, and the storage area to be assigned is determined in accordance with the calculated evaluation value.
It is therefore possible to configure a system having a high efficiency capable of assigning each storage device or each storage area.
Other objects, features and advantages of the present invention will become apparent from the following description of the embodiments taken in conjunction with the accompanying drawings.